The present invention relates to a pressure seal method for a fiber product feed in and take out parts provided at a high pressure steamer, and a pressure seal apparatus simultaneously employing air balance of a high pressure steamer used in said method.
Heretofore, pressure seal method of a high pressure steamer has had such shortcomings that steam which is pressure introduced into a vessel body of a high pressure steamer has a high temperature during operation making it difficult to retain the atmosphere (pressure, temperature, etc.) of the steam at a state suitable for processing fiber products, further the temperature within vessel body rises due to the high temperature of the steam causing thermal expansion to take place at each sealing member of the device of the steamer. Moreover, as the coefficient of thermal expansion of each of the seal members is different from each other each sealing member placed in pressure contact with each other by great pressure for necessity of sealing gas with high pressure within the vessel chamber has strain deformation, causing pressure seal leakage thus lowering safety of operation, furthermore, durable life of the seal apparatus is shortened, and time, trouble and expenses required for maintenance of apparatus go up, also adversely affecting operating efficiency.
Pressure seal apparatus for a fiber product feed in and take out parts of a high pressure steamer vessel body used in a conventional pressure sealing method ordinarily has such method as providing a roll seal mechanism consisting of such sealing members as a pair of left and right seal rolls rotating in contact with each other, a seal block installed at the fiber feed in and take out openings of vessel body, and intermediate rolls intervening between the seal rolls and the seal block, etc.
However, in a sealing apparatus having such a set-up, the temperature within steamer vessel body rises during operation as mentioned above and each sealing member of the sealing apparatus directly receives the effect of high temperature and causes thermal expansion, causing strain deformation at each sealing member in contact with each other because coefficient of thermal expansion is different from each other and causing pressure seal leakage, thereby it becomes difficult to retain the atmosphere of steam pressure introduced into vessel body at such constant state as suited for processing of fiber products, and the elastic substance for the seal roll becomes fragile because of defects of a mechanism to adjust the change in the atmosphere, etc., shortening the durable life of the seal apparatus.
Furthermore, in a seal apparatus having above mentioned mechanism the pressure contact points between a pair of left and right seal rolls and the sealing member which pressure contacts with circumferential surface of the rolls, that is, the pressure sealing points in the circumferential direction of the rolls are such that the nip planes formed by the seal rolls form almost right angle against the axial centers of the rolls, therefore, the pressure receiving plane of the seal roll circumferential plane to receive the pressure within the vessel is great and the pressure giving force over seal roll required for formation of nip plane needs to be comparatively large. Therefore, driving force for such seal roll becomes large, further the effect over fiber products passing through nip plane also increases.
The present invention is to prevent various shortcomings generated in conventional method and its apparatus in a pressure seal method simultaneously employing air balance of a high pressure steamer and an apparatus to embody said method, and realized a method and an apparatus in which pressure seal operation is done safely and surely, and the roll seal mechanism of the seal apparatus used will not be directly affected by high temperature leaving no fear of deformation and becoming fragile, thus securing a long durable life.